The present invention relates to a capacitor module in which a plurality of capacitors is mounted on a wiring board.
FIG. 9 is a perspective view showing the configuration of such a conventional capacitor module. FIG. 10 is a perspective view showing a wiring board used for the capacitor module. In FIGS. 9 and 10, reference numeral 15 denotes a wiring board, reference numeral 15a denotes mounting holes for inserting lead wires 16b and 16c of capacitors 16 provided on the wiring board 15, and reference numeral 15b denotes mounting holes which are formed on the wiring board 15 to mount the capacitor module into equipment to be used. Reference numeral 16 denotes capacitors. The capacitor 16 contains a capacitor element having an electrolytic solution within a metallic case 16a in a cylinder shape with a bottom (both of the case and the element are not shown), and the pair of lead wires 16b and 16c for external connection is drawn from the capacitor element.
The conventional capacitor module in such an arrangement is configured, by fitting the pairs of the lead wires 16b and 16c of the capacitors 16 in the mounting holes 15a provided on the wiring board 15, before the lead wires 16b and 16c are soldered on the back so as to be electrically connected to wiring circuits (not shown) provided on the wiring board 15, and the plurality of capacitors 16 is mounted on the single wiring board 15.
Besides, for example, Patent Document 1 (Japanese Patent Laid-Open No. 6-275471) has been known as prior art document information.
In the above conventional capacitor module, such a capacitor module is mounted on equipment to be used via the mounting holes 15b provided on the wiring board 15 for use. In some mounting conditions, however, the weight of the plurality of capacitors 16 (several hundreds grams to several kilograms) is applied onto the single wiring board 15, resulting in distortion and deformation in the wiring board 15. Further, in some working conditions, particularly when vibration occurs, breaks appear on the mounting holes 15b of the wiring board 15 and the main body of the wiring board 15 or cracks appear on soldered parts which electrically connect the pair of lead wires 16b and 16c of the capacitors 16 to the wiring circuits provided on the wiring board 15.
Moreover, when abnormal current passes through the capacitor 16, an explosion-proof valve 16d is operated which is provided on the metallic case 16a of the capacitor 16, and the driving electrolytic solution that is filled in the capacitor element contained within the metallic case 16a is discharged from the explosion-proof valve 16d. Since the discharged electrolytic solution for driving is scattered to surrounding parts, a short circuit occurs and another adjacent electronic equipment similarly develops a short circuit in the worst case.
The present invention has as its objective the provision of a reliable capacitor module which can solve such conventional problems, eliminate a weight load applied onto a wiring board, and prevent the occurrence of short circuits even when an explosion-proof valve is operated.
In order to solve the above-described problems, a first embodiment of the present invention is constituted by a mounting plate having a plurality of first recesses formed on the upper surface thereof, a plurality of capacitors at least partially held in the first recesses of the mounting plate, and a wiring board electrically connected with lead wires drawn from each capacitor, the mounting plate and the wiring board being opposed to each other via the capacitors, the mounting plate being devised for mounting the capacitor module into an equipment for use. With this configuration, the weight of the plurality of capacitors is totally supported by the mounting plate. Hence, it is possible to eliminate a weight load applied onto the wiring board and prevent the occurrence of a break on the wiring board, thereby providing a reliable capacitor module.
Further, the present invention further comprises second recesses formed in the plurality of first recesses on the upper surface of the mounting plate, the second recesses being smaller in diameter than the first recesses. With this configuration, even when an explosion-proof valve provided on the bottom of the case of the capacitor is operated to discharge an electrolytic solution for driving, the discharged electrolytic solution for driving is well stored in the second recess and is not scattered to the outside. Thus, short circuits do not occur and a reliable capacitor module can be provided.
As described above, in the capacitor module according to the first embodiment of the present invention, the bottoms of the metallic cases of the capacitors are fit and held in the first recesses formed on the mounting plate, the lead wires drawn from the upper surface of each capacitor are electrically connected via the wiring board in this state. Since the mounting plate mechanically fixes the plurality of capacitors, a weight load of the plurality of capacitors is not applied onto the wiring board. Therefore, it is possible to completely prevent the wiring board from being distorted or deformed by the weight load of the plurality of capacitors, prevent vibration from breaking the main body of the wiring board, and prevent a crack on a soldered part between the lead wires of the capacitor and the wiring board.
Next, according to a second embodiment of the present invention, amounting plate is constituted by a holding member and a main body, the holding member having a plurality of holes for holding capacitors and being fit in the main body. With this configuration, even when the used capacitors are changed, it is possible to respond to the change just by changing the holding member, thereby reducing the total cost.
Further, the present invention is configured such that ribs and/or slits are provided in each hole of the holding member constituting the mounting plate. With this configuration, it is possible to more positively hold the capacitors and remarkably improve holding force.
Moreover, the present invention is configured such that the main body constituting the mounting plate has storage recesses for storing electronic components other than capacitors. With this configuration, it is possible to integrally mount a control circuit and so on to achieve a multi-function capacitor module.
Additionally, a forming part formed by bending a lead wire is provided between the main body of the capacitor and a wiring board insertion part of the lead wire drawn from the capacitors. With this configuration, it is possible to maintain a fixed distance between the main body of the capacitor and the wiring board, thereby reducing heat stress applied to the lead wire.
As described above, in the capacitor module according to the second embodiment of the present invention, the second recesses are provided in the first recesses of the mounting plate. Hence, even in the case where an explosion-proof valve is operated to discharge an electrolytic solution for driving when abnormal current passes though the capacitors, the discharged electrolytic solution for driving is well stored in the second recesses provided in the first recesses of the mounting plate and is not scattered to the surrounding parts, thereby preventing the occurrence of short circuits.